From: Yang Li <yang.li@amlogic.com>
Date: Mon, 7 Jul 2025 02:38:17 +0000 (+0800)
Subject: Bluetooth: ISO: Support SCM_TIMESTAMPING for ISO TS
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef568ae04ead4d132481550fde36fcdd29a31b3b;p=thirdparty%2Flinux.git

Bluetooth: ISO: Support SCM_TIMESTAMPING for ISO TS

User-space applications (e.g. PipeWire) depend on
ISO-formatted timestamps for precise audio sync.

The ISO ts is based on the controller’s clock domain,
so hardware timestamping (hwtimestamp) must be used.

Ref: Documentation/networking/timestamping.rst,
section 3.1 Hardware Timestamping.

Signed-off-by: Yang Li <yang.li@amlogic.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 2f229f2077e83..2f45e46a9b6ae 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -2289,6 +2289,7 @@ static void iso_disconn_cfm(struct hci_conn *hcon, __u8 reason)
 void iso_recv(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 {
 	struct iso_conn *conn = hcon->iso_data;
+	struct skb_shared_hwtstamps *hwts;
 	__u16 pb, ts, len, sn;
 
 	if (!conn)
@@ -2312,13 +2313,16 @@ void iso_recv(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 		if (ts) {
 			struct hci_iso_ts_data_hdr *hdr;
 
-			/* TODO: add timestamp to the packet? */
 			hdr = skb_pull_data(skb, HCI_ISO_TS_DATA_HDR_SIZE);
 			if (!hdr) {
 				BT_ERR("Frame is too short (len %d)", skb->len);
 				goto drop;
 			}
 
+			/*  Record the timestamp to skb */
+			hwts = skb_hwtstamps(skb);
+			hwts->hwtstamp = us_to_ktime(le32_to_cpu(hdr->ts));
+
 			sn = __le16_to_cpu(hdr->sn);
 			len = __le16_to_cpu(hdr->slen);
 		} else {
@@ -2370,6 +2374,13 @@ void iso_recv(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 		skb_copy_from_linear_data(skb, skb_put(conn->rx_skb, skb->len),
 					  skb->len);
 		conn->rx_len = len - skb->len;
+
+		/* Copy hw timestamp from skb to rx_skb if present */
+		if (ts) {
+			hwts = skb_hwtstamps(conn->rx_skb);
+			hwts->hwtstamp = skb_hwtstamps(skb)->hwtstamp;
+		}
+
 		break;
 
 	case ISO_CONT: